The present invention relates generally to techniques for analyzing a musical score and more particularly to a technique for associating musical score image data and logical musical score data.
A musical score of a given music can be expressed not only as data indicative of a visible image (such data will hereinafter be referred to as “musical score image data”) of the musical score but also as data describing content of the musical score as logical music information by use of a particular data description language (such data will hereinafter be referred to as “logical musical data”). A typical example of the musical score image data is a PDF file (Portable Document File), and a typical example of the logical musical data is a file of the MusicXML (eXtensible Markup Language) format.
Because the musical score image data expresses a musical score as an image, it is difficult for a computer to recognize content, such as musical symbol, of the musical score accurately and in detail as computer-interpretable information, although the musical score can be displayed in a form (layout) exactly as intended by a creator. Japanese Patent Application Laid-open Publication Nos. 2012-073769 and 2012-138009, for example, disclose musical score recognition techniques for recognizing musical symbols by analyzing an image of a musical score; actually however, these disclosed musical score recognition technique would suffer from a problem of recognition errors. The logical musical score data, on the other hand, expresses a musical score as logical information, and thus, the logical musical score data has a character that a form of display of the musical score varies (i.e., reproduction reliability of a layout of the musical score) depending on an algorithm of a rendering engine that generates an image from the logical musical score, although the logical musical score data allows content, such as musical symbols, of the musical score to be grasped accurately and in detail.
As seen from the foregoing, the musical score image data and the logical musical score data have both advantages and disadvantages. If such musical score image data and logical musical score data can be used in combination to make up for each other's disadvantages, it may be possible to realize diversified use of a musical score. For example, it may be possible to realize use of a musical score where music piece reproduction (automatic performance) using the logical musical score data and musical score display using the musical score image data are performed in parallel with each other, and where a current reproduced position of the music piece in the musical score is displayed in a highlighted manner. However, because note-by-note correspondence relationship is unclear between the musical score indicated by the musical score image data and the musical score indicated by the logical musical score data, using the musical score image data and logical musical score data in combination is difficult in reality.